<!DOCTYPE html>
<html lang="zh-CN">
    <head>
        <meta charset="utf-8">
        <meta name="viewport" content="width=device-width, initial-scale=1">
        <meta name="robots" content="noodp" />
        <title>设计模式之原型模式——浅拷贝和深拷贝 - MC&#39; blog</title><meta name="Description" content="MC&#39; Blog，不定期的技术分享"><meta property="og:title" content="设计模式之原型模式——浅拷贝和深拷贝" />
<meta property="og:description" content="原型模式 原型模式的定义 Specify the kinds of create using prototypical ihnstance, and create new objects by copying this prototy. 用原型实例指定创建对象的种类，并且通过拷贝这些原型创建新的对象。 原型模式就是通过原来的" />
<meta property="og:type" content="article" />
<meta property="og:url" content="http://example.org/%E5%8E%9F%E5%9E%8B%E6%A8%A1%E5%BC%8F/" /><meta property="og:image" content="http://example.org/logo.png"/><meta property="article:section" content="posts" />
<meta property="article:published_time" content="2018-10-20T10:09:00+08:00" />
<meta property="article:modified_time" content="2018-10-20T10:09:00+08:00" /><meta property="og:site_name" content="MC&#39; Blog" />
<meta name="twitter:card" content="summary_large_image"/>
<meta name="twitter:image" content="http://example.org/logo.png"/>

<meta name="twitter:title" content="设计模式之原型模式——浅拷贝和深拷贝"/>
<meta name="twitter:description" content="原型模式 原型模式的定义 Specify the kinds of create using prototypical ihnstance, and create new objects by copying this prototy. 用原型实例指定创建对象的种类，并且通过拷贝这些原型创建新的对象。 原型模式就是通过原来的"/>
<meta name="application-name" content="MC&#39; Blog">
<meta name="apple-mobile-web-app-title" content="MC&#39; Blog"><meta name="theme-color" content="#ffffff"><meta name="msapplication-TileColor" content="#da532c"><link rel="shortcut icon" type="image/x-icon" href="/favicon.ico" />
        <link rel="icon" type="image/png" sizes="32x32" href="/favicon-32x32.png">
        <link rel="icon" type="image/png" sizes="16x16" href="/favicon-16x16.png"><link rel="apple-touch-icon" sizes="180x180" href="/apple-touch-icon.png"><link rel="mask-icon" href="/safari-pinned-tab.svg" color="#5bbad5"><link rel="manifest" href="/site.webmanifest"><link rel="canonical" href="http://example.org/%E5%8E%9F%E5%9E%8B%E6%A8%A1%E5%BC%8F/" /><link rel="prev" href="http://example.org/%E4%BB%A3%E7%90%86%E6%A8%A1%E5%BC%8F/" /><link rel="next" href="http://example.org/%E8%B4%A3%E4%BB%BB%E9%93%BE%E6%A8%A1%E5%BC%8F/" /><link rel="stylesheet" href="/css/style.min.css"><link rel="preload" href="https://cdn.jsdelivr.net/npm/@fortawesome/fontawesome-free@6.1.1/css/all.min.css" as="style" onload="this.onload=null;this.rel='stylesheet'">
        <noscript><link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/@fortawesome/fontawesome-free@6.1.1/css/all.min.css"></noscript><link rel="preload" href="https://cdn.jsdelivr.net/npm/animate.css@4.1.1/animate.min.css" as="style" onload="this.onload=null;this.rel='stylesheet'">
        <noscript><link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/animate.css@4.1.1/animate.min.css"></noscript><script type="application/ld+json">
    {
        "@context": "http://schema.org",
        "@type": "BlogPosting",
        "headline": "设计模式之原型模式——浅拷贝和深拷贝",
        "inLanguage": "zh-CN",
        "mainEntityOfPage": {
            "@type": "WebPage",
            "@id": "http:\/\/example.org\/%E5%8E%9F%E5%9E%8B%E6%A8%A1%E5%BC%8F\/"
        },"image": ["http:\/\/example.org\/images\/Apple-Devices-Preview.png"],"genre": "posts","keywords": "设计模式","wordcount":  1332 ,
        "url": "http:\/\/example.org\/%E5%8E%9F%E5%9E%8B%E6%A8%A1%E5%BC%8F\/","datePublished": "2018-10-20T10:09:00+08:00","dateModified": "2018-10-20T10:09:00+08:00","license": "This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.","publisher": {
            "@type": "Organization",
            "name": "xxxx","logo": {
                    "@type": "ImageObject",
                    "url": "http:\/\/example.org\/images\/avatar.png",
                    "width":  528 ,
                    "height":  560 
                }},"author": {
                "@type": "Person",
                "name": "MC"
            },"description": ""
    }
    </script></head>
    <body data-header-desktop="fixed" data-header-mobile="auto"><script type="text/javascript">(window.localStorage && localStorage.getItem('theme') ? localStorage.getItem('theme') === 'dark' : ('auto' === 'auto' ? window.matchMedia('(prefers-color-scheme: dark)').matches : 'auto' === 'dark')) && document.body.setAttribute('theme', 'dark');</script>

        <div id="mask"></div><div class="wrapper"><header class="desktop" id="header-desktop">
    <div class="header-wrapper">
        <div class="header-title">
            <a href="/" title="MC&#39; blog"><span class="header-title-pre"><i class='far fa-kiss-wink-heart fa-fw' aria-hidden='true'></i></span>MC&#39; Blog</a>
        </div>
        <div class="menu">
            <div class="menu-inner"><a class="menu-item" href="/posts/"> 所有文章 </a><a class="menu-item" href="/tags/"> 标签 </a><a class="menu-item" href="/categories/"> 分类 </a><a class="menu-item" href="/categories/documentation/"> 文档 </a><a class="menu-item" href="/about/"> 关于 </a><a class="menu-item" href="https://github.com/woxin123" title="GitHub" rel="noopener noreffer" target="_blank"><i class='fab fa-github fa-fw' aria-hidden='true'></i>  </a><span class="menu-item delimiter"></span><span class="menu-item search" id="search-desktop">
                        <input type="text" placeholder="搜索文章标题或内容..." id="search-input-desktop">
                        <a href="javascript:void(0);" class="search-button search-toggle" id="search-toggle-desktop" title="搜索">
                            <i class="fas fa-search fa-fw" aria-hidden="true"></i>
                        </a>
                        <a href="javascript:void(0);" class="search-button search-clear" id="search-clear-desktop" title="清空">
                            <i class="fas fa-times-circle fa-fw" aria-hidden="true"></i>
                        </a>
                        <span class="search-button search-loading" id="search-loading-desktop">
                            <i class="fas fa-spinner fa-fw fa-spin" aria-hidden="true"></i>
                        </span>
                    </span><a href="javascript:void(0);" class="menu-item theme-switch" title="切换主题">
                    <i class="fas fa-adjust fa-fw" aria-hidden="true"></i>
                </a></div>
        </div>
    </div>
</header><header class="mobile" id="header-mobile">
    <div class="header-container">
        <div class="header-wrapper">
            <div class="header-title">
                <a href="/" title="MC&#39; blog"><span class="header-title-pre"><i class='far fa-kiss-wink-heart fa-fw' aria-hidden='true'></i></span>MC&#39; Blog</a>
            </div>
            <div class="menu-toggle" id="menu-toggle-mobile">
                <span></span><span></span><span></span>
            </div>
        </div>
        <div class="menu" id="menu-mobile"><div class="search-wrapper">
                    <div class="search mobile" id="search-mobile">
                        <input type="text" placeholder="搜索文章标题或内容..." id="search-input-mobile">
                        <a href="javascript:void(0);" class="search-button search-toggle" id="search-toggle-mobile" title="搜索">
                            <i class="fas fa-search fa-fw" aria-hidden="true"></i>
                        </a>
                        <a href="javascript:void(0);" class="search-button search-clear" id="search-clear-mobile" title="清空">
                            <i class="fas fa-times-circle fa-fw" aria-hidden="true"></i>
                        </a>
                        <span class="search-button search-loading" id="search-loading-mobile">
                            <i class="fas fa-spinner fa-fw fa-spin" aria-hidden="true"></i>
                        </span>
                    </div>
                    <a href="javascript:void(0);" class="search-cancel" id="search-cancel-mobile">
                        取消
                    </a>
                </div><a class="menu-item" href="/posts/" title="">所有文章</a><a class="menu-item" href="/tags/" title="">标签</a><a class="menu-item" href="/categories/" title="">分类</a><a class="menu-item" href="/categories/documentation/" title="">文档</a><a class="menu-item" href="/about/" title="">关于</a><a class="menu-item" href="https://github.com/woxin123" title="GitHub" rel="noopener noreffer" target="_blank"><i class='fab fa-github fa-fw' aria-hidden='true'></i></a><a href="javascript:void(0);" class="menu-item theme-switch" title="切换主题">
                <i class="fas fa-adjust fa-fw" aria-hidden="true"></i>
            </a></div>
    </div>
</header><div class="search-dropdown desktop">
        <div id="search-dropdown-desktop"></div>
    </div>
    <div class="search-dropdown mobile">
        <div id="search-dropdown-mobile"></div>
    </div><main class="main">
                <div class="container"><div class="toc" id="toc-auto">
            <h2 class="toc-title">目录</h2>
            <div class="toc-content" id="toc-content-auto"></div>
        </div><article class="page single"><h1 class="single-title animate__animated animate__flipInX">设计模式之原型模式——浅拷贝和深拷贝</h1><div class="post-meta">
            <div class="post-meta-line"><span class="post-author"><a href="/" title="Author" rel="author" class="author"><i class="fas fa-user-circle fa-fw" aria-hidden="true"></i>MC</a></span>&nbsp;<span class="post-category">收录于 <a href="/categories/%E8%AE%BE%E8%AE%A1%E6%A8%A1%E5%BC%8F/"><i class="far fa-folder fa-fw" aria-hidden="true"></i>设计模式</a></span></div>
            <div class="post-meta-line"><i class="far fa-calendar-alt fa-fw" aria-hidden="true"></i>&nbsp;<time datetime="2018-10-20">2018-10-20</time>&nbsp;<i class="fas fa-pencil-alt fa-fw" aria-hidden="true"></i>&nbsp;约 1332 字&nbsp;
                <i class="far fa-clock fa-fw" aria-hidden="true"></i>&nbsp;预计阅读 3 分钟&nbsp;<span id="/%E5%8E%9F%E5%9E%8B%E6%A8%A1%E5%BC%8F/" class="leancloud_visitors" data-flag-title="设计模式之原型模式——浅拷贝和深拷贝">
                        <i class="far fa-eye fa-fw" aria-hidden="true"></i>&nbsp;<span class=leancloud-visitors-count></span>&nbsp;次阅读
                    </span>&nbsp;</div>
        </div><div class="details toc" id="toc-static"  data-kept="">
                <div class="details-summary toc-title">
                    <span>目录</span>
                    <span><i class="details-icon fas fa-angle-right" aria-hidden="true"></i></span>
                </div>
                <div class="details-content toc-content" id="toc-content-static"><nav id="TableOfContents">
  <ul>
    <li><a href="#原型模式的定义">原型模式的定义</a></li>
    <li><a href="#原型模式的优点">原型模式的优点</a></li>
    <li><a href="#浅拷贝和深拷贝">浅拷贝和深拷贝</a></li>
    <li><a href="#浅拷贝">浅拷贝</a>
      <ul>
        <li><a href="#深拷贝">深拷贝</a></li>
      </ul>
    </li>
    <li><a href="#参考">参考</a></li>
  </ul>
</nav></div>
            </div><div class="content" id="content"><h1 id="原型模式">原型模式</h1>
<h2 id="原型模式的定义">原型模式的定义</h2>
<p>Specify the kinds of create using prototypical ihnstance, and create new objects by copying this prototy.</p>
<p>用原型实例指定创建对象的种类，并且通过拷贝这些原型创建新的对象。</p>
<p>原型模式就是通过原来的对象通过拷贝创建一个新的对象。</p>
<p>Java提供了一个Cloneable接口来表示一个类所产生的对象是可拷贝的，而这里的这个Cloneable只是用来标识这个类的对象是可以拷贝的，便没有其他什么作用。
众所周知Java中的所有对象都集成自Object类，这一个类中有<code>clone()</code>方法。</p>
<p>原型模式的通过代码如下：</p>
<div class="highlight"><div class="chroma">
<table class="lntable"><tr><td class="lntd">
<pre tabindex="0" class="chroma"><code><span class="lnt">1
</span></code></pre></td>
<td class="lntd">
<pre tabindex="0" class="chroma"><code class="language-java" data-lang="java"><span class="line"><span class="cl"><span class="kd">protected</span> <span class="kd">native</span> <span class="n">Object</span> <span class="nf">clone</span><span class="o">()</span> <span class="kd">throws</span> <span class="n">CloneNotSupportedException</span><span class="o">;</span>
</span></span></code></pre></td></tr></table>
</div>
</div><p>这是一个native层的方法，作用是复制对象中的内容。</p>
<div class="highlight"><div class="chroma">
<table class="lntable"><tr><td class="lntd">
<pre tabindex="0" class="chroma"><code><span class="lnt"> 1
</span><span class="lnt"> 2
</span><span class="lnt"> 3
</span><span class="lnt"> 4
</span><span class="lnt"> 5
</span><span class="lnt"> 6
</span><span class="lnt"> 7
</span><span class="lnt"> 8
</span><span class="lnt"> 9
</span><span class="lnt">10
</span><span class="lnt">11
</span><span class="lnt">12
</span><span class="lnt">13
</span><span class="lnt">14
</span></code></pre></td>
<td class="lntd">
<pre tabindex="0" class="chroma"><code class="language-java" data-lang="java"><span class="line"><span class="cl"><span class="kd">public</span> <span class="kd">class</span> <span class="nc">PrototypeCLass</span> <span class="kd">implements</span> <span class="n">Cloneable</span> <span class="o">{</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="nd">@Override</span>
</span></span><span class="line"><span class="cl">    <span class="kd">protected</span> <span class="n">Object</span> <span class="nf">clone</span><span class="o">()</span>  <span class="o">{</span>
</span></span><span class="line"><span class="cl">        <span class="n">PrototypeCLass</span> <span class="n">prototypeCLass</span> <span class="o">=</span> <span class="kc">null</span><span class="o">;</span>
</span></span><span class="line"><span class="cl">        <span class="k">try</span> <span class="o">{</span>
</span></span><span class="line"><span class="cl">            <span class="n">prototypeCLass</span> <span class="o">=</span> <span class="o">(</span><span class="n">PrototypeCLass</span><span class="o">)</span> <span class="kd">super</span><span class="o">.</span><span class="na">clone</span><span class="o">();</span>
</span></span><span class="line"><span class="cl">        <span class="o">}</span> <span class="k">catch</span> <span class="o">(</span><span class="n">CloneNotSupportedException</span> <span class="n">e</span><span class="o">)</span> <span class="o">{</span>
</span></span><span class="line"><span class="cl">            <span class="c1">// 异常处理
</span></span></span><span class="line"><span class="cl"><span class="c1"></span>        <span class="o">}</span>
</span></span><span class="line"><span class="cl">        
</span></span><span class="line"><span class="cl">        <span class="k">return</span> <span class="n">prototypeCLass</span><span class="o">;</span>
</span></span><span class="line"><span class="cl">    <span class="o">}</span>
</span></span><span class="line"><span class="cl"><span class="o">}</span>
</span></span></code></pre></td></tr></table>
</div>
</div><h2 id="原型模式的优点">原型模式的优点</h2>
<ul>
<li>
<p>性能优良
原型模式是<span style="color: green">在内存中进行二进制流的拷贝，要比直接new一个对象性能好的多</span>，特别是在循环体内产生大量的对象，原型模式能更好的体现它的优点。</p>
</li>
<li>
<p>逃避使用构造函数的约束
这一点既是优点也是缺点，直接在内存中拷贝，构造函数是不会执行的。优点是减少了约束，但缺点也是减少了约束。</p>
</li>
</ul>
<h2 id="浅拷贝和深拷贝">浅拷贝和深拷贝</h2>
<h2 id="浅拷贝">浅拷贝</h2>
<p>定义一个Student类，属性有id，姓名和成绩，如下：</p>
<div class="highlight"><div class="chroma">
<table class="lntable"><tr><td class="lntd">
<pre tabindex="0" class="chroma"><code><span class="lnt"> 1
</span><span class="lnt"> 2
</span><span class="lnt"> 3
</span><span class="lnt"> 4
</span><span class="lnt"> 5
</span><span class="lnt"> 6
</span><span class="lnt"> 7
</span><span class="lnt"> 8
</span><span class="lnt"> 9
</span><span class="lnt">10
</span><span class="lnt">11
</span><span class="lnt">12
</span><span class="lnt">13
</span><span class="lnt">14
</span><span class="lnt">15
</span><span class="lnt">16
</span><span class="lnt">17
</span><span class="lnt">18
</span><span class="lnt">19
</span><span class="lnt">20
</span><span class="lnt">21
</span><span class="lnt">22
</span><span class="lnt">23
</span><span class="lnt">24
</span><span class="lnt">25
</span><span class="lnt">26
</span><span class="lnt">27
</span><span class="lnt">28
</span><span class="lnt">29
</span><span class="lnt">30
</span><span class="lnt">31
</span><span class="lnt">32
</span><span class="lnt">33
</span><span class="lnt">34
</span><span class="lnt">35
</span><span class="lnt">36
</span><span class="lnt">37
</span><span class="lnt">38
</span><span class="lnt">39
</span><span class="lnt">40
</span><span class="lnt">41
</span><span class="lnt">42
</span><span class="lnt">43
</span><span class="lnt">44
</span><span class="lnt">45
</span><span class="lnt">46
</span><span class="lnt">47
</span><span class="lnt">48
</span><span class="lnt">49
</span><span class="lnt">50
</span><span class="lnt">51
</span><span class="lnt">52
</span><span class="lnt">53
</span><span class="lnt">54
</span><span class="lnt">55
</span><span class="lnt">56
</span></code></pre></td>
<td class="lntd">
<pre tabindex="0" class="chroma"><code class="language-java" data-lang="java"><span class="line"><span class="cl"><span class="kd">public</span> <span class="kd">class</span> <span class="nc">Student</span> <span class="kd">implements</span> <span class="n">Cloneable</span> <span class="o">{</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="kd">private</span> <span class="n">Integer</span> <span class="n">id</span><span class="o">;</span>
</span></span><span class="line"><span class="cl">    <span class="kd">private</span> <span class="n">String</span> <span class="n">name</span><span class="o">;</span>
</span></span><span class="line"><span class="cl">    <span class="kd">private</span> <span class="n">Map</span><span class="o">&lt;</span><span class="n">String</span><span class="o">,</span> <span class="n">Double</span><span class="o">&gt;</span> <span class="n">scores</span><span class="o">;</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="kd">public</span> <span class="nf">Student</span><span class="o">(</span><span class="n">Integer</span> <span class="n">id</span><span class="o">,</span> <span class="n">String</span> <span class="n">name</span><span class="o">,</span> <span class="n">Map</span><span class="o">&lt;</span><span class="n">String</span><span class="o">,</span> <span class="n">Double</span><span class="o">&gt;</span> <span class="n">scores</span><span class="o">)</span> <span class="o">{</span>
</span></span><span class="line"><span class="cl">        <span class="k">this</span><span class="o">.</span><span class="na">id</span> <span class="o">=</span> <span class="n">id</span><span class="o">;</span>
</span></span><span class="line"><span class="cl">        <span class="k">this</span><span class="o">.</span><span class="na">name</span> <span class="o">=</span> <span class="n">name</span><span class="o">;</span>
</span></span><span class="line"><span class="cl">        <span class="k">this</span><span class="o">.</span><span class="na">scores</span> <span class="o">=</span> <span class="n">scores</span><span class="o">;</span>
</span></span><span class="line"><span class="cl">    <span class="o">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="kd">public</span> <span class="n">Integer</span> <span class="nf">getId</span><span class="o">()</span> <span class="o">{</span>
</span></span><span class="line"><span class="cl">        <span class="k">return</span> <span class="n">id</span><span class="o">;</span>
</span></span><span class="line"><span class="cl">    <span class="o">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="kd">public</span> <span class="kt">void</span> <span class="nf">setId</span><span class="o">(</span><span class="n">Integer</span> <span class="n">id</span><span class="o">)</span> <span class="o">{</span>
</span></span><span class="line"><span class="cl">        <span class="k">this</span><span class="o">.</span><span class="na">id</span> <span class="o">=</span> <span class="n">id</span><span class="o">;</span>
</span></span><span class="line"><span class="cl">    <span class="o">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="kd">public</span> <span class="n">String</span> <span class="nf">getName</span><span class="o">()</span> <span class="o">{</span>
</span></span><span class="line"><span class="cl">        <span class="k">return</span> <span class="n">name</span><span class="o">;</span>
</span></span><span class="line"><span class="cl">    <span class="o">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="kd">public</span> <span class="kt">void</span> <span class="nf">setName</span><span class="o">(</span><span class="n">String</span> <span class="n">name</span><span class="o">)</span> <span class="o">{</span>
</span></span><span class="line"><span class="cl">        <span class="k">this</span><span class="o">.</span><span class="na">name</span> <span class="o">=</span> <span class="n">name</span><span class="o">;</span>
</span></span><span class="line"><span class="cl">    <span class="o">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="kd">public</span> <span class="n">Map</span><span class="o">&lt;</span><span class="n">String</span><span class="o">,</span> <span class="n">Double</span><span class="o">&gt;</span> <span class="nf">getScores</span><span class="o">()</span> <span class="o">{</span>
</span></span><span class="line"><span class="cl">        <span class="k">return</span> <span class="n">scores</span><span class="o">;</span>
</span></span><span class="line"><span class="cl">    <span class="o">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="kd">public</span> <span class="kt">void</span> <span class="nf">setScores</span><span class="o">(</span><span class="n">Map</span><span class="o">&lt;</span><span class="n">String</span><span class="o">,</span> <span class="n">Double</span><span class="o">&gt;</span> <span class="n">scores</span><span class="o">)</span> <span class="o">{</span>
</span></span><span class="line"><span class="cl">        <span class="k">this</span><span class="o">.</span><span class="na">scores</span> <span class="o">=</span> <span class="n">scores</span><span class="o">;</span>
</span></span><span class="line"><span class="cl">    <span class="o">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="nd">@Override</span>
</span></span><span class="line"><span class="cl">    <span class="kd">protected</span> <span class="n">Student</span> <span class="nf">clone</span><span class="o">()</span>  <span class="o">{</span>
</span></span><span class="line"><span class="cl">        <span class="n">Student</span> <span class="n">student</span> <span class="o">=</span> <span class="kc">null</span><span class="o">;</span>
</span></span><span class="line"><span class="cl">        <span class="k">try</span> <span class="o">{</span>
</span></span><span class="line"><span class="cl">            <span class="n">student</span> <span class="o">=</span> <span class="o">(</span><span class="n">Student</span><span class="o">)</span> <span class="kd">super</span><span class="o">.</span><span class="na">clone</span><span class="o">();</span>
</span></span><span class="line"><span class="cl">        <span class="o">}</span> <span class="k">catch</span> <span class="o">(</span><span class="n">CloneNotSupportedException</span> <span class="n">e</span><span class="o">)</span> <span class="o">{</span>
</span></span><span class="line"><span class="cl">            <span class="n">e</span><span class="o">.</span><span class="na">printStackTrace</span><span class="o">();</span>
</span></span><span class="line"><span class="cl">        <span class="o">}</span>
</span></span><span class="line"><span class="cl">        <span class="k">return</span> <span class="n">student</span><span class="o">;</span>
</span></span><span class="line"><span class="cl">    <span class="o">}</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">    <span class="nd">@Override</span>
</span></span><span class="line"><span class="cl">    <span class="kd">public</span> <span class="n">String</span> <span class="nf">toString</span><span class="o">()</span> <span class="o">{</span>
</span></span><span class="line"><span class="cl">        <span class="k">return</span> <span class="s">&#34;Student{&#34;</span> <span class="o">+</span>
</span></span><span class="line"><span class="cl">                <span class="s">&#34;id=&#34;</span> <span class="o">+</span> <span class="n">id</span> <span class="o">+</span>
</span></span><span class="line"><span class="cl">                <span class="s">&#34;, name=&#39;&#34;</span> <span class="o">+</span> <span class="n">name</span> <span class="o">+</span> <span class="sc">&#39;\&#39;&#39;</span> <span class="o">+</span>
</span></span><span class="line"><span class="cl">                <span class="s">&#34;, scores=&#34;</span> <span class="o">+</span> <span class="n">scores</span> <span class="o">+</span>
</span></span><span class="line"><span class="cl">                <span class="sc">&#39;}&#39;</span><span class="o">;</span>
</span></span><span class="line"><span class="cl">    <span class="o">}</span>
</span></span><span class="line"><span class="cl"><span class="o">}</span>
</span></span></code></pre></td></tr></table>
</div>
</div><p>上面的Student类实现了Cloneable接口，重写现了Objecy类中的clone()方法。
下面写一个测试类，来测试这个类。</p>
<div class="highlight"><div class="chroma">
<table class="lntable"><tr><td class="lntd">
<pre tabindex="0" class="chroma"><code><span class="lnt"> 1
</span><span class="lnt"> 2
</span><span class="lnt"> 3
</span><span class="lnt"> 4
</span><span class="lnt"> 5
</span><span class="lnt"> 6
</span><span class="lnt"> 7
</span><span class="lnt"> 8
</span><span class="lnt"> 9
</span><span class="lnt">10
</span><span class="lnt">11
</span><span class="lnt">12
</span><span class="lnt">13
</span><span class="lnt">14
</span><span class="lnt">15
</span><span class="lnt">16
</span><span class="lnt">17
</span></code></pre></td>
<td class="lntd">
<pre tabindex="0" class="chroma"><code class="language-java" data-lang="java"><span class="line"><span class="cl"><span class="kd">public</span> <span class="kd">class</span> <span class="nc">Main</span> <span class="o">{</span>
</span></span><span class="line"><span class="cl">    <span class="kd">public</span> <span class="kd">static</span> <span class="kt">void</span> <span class="nf">main</span><span class="o">(</span><span class="n">String</span><span class="o">[]</span> <span class="n">args</span><span class="o">)</span> <span class="o">{</span>
</span></span><span class="line"><span class="cl">        <span class="n">Map</span><span class="o">&lt;</span><span class="n">String</span><span class="o">,</span> <span class="n">Double</span><span class="o">&gt;</span> <span class="n">scores</span> <span class="o">=</span> <span class="k">new</span> <span class="n">HashMap</span><span class="o">&lt;&gt;();</span>
</span></span><span class="line"><span class="cl">        <span class="n">scores</span><span class="o">.</span><span class="na">put</span><span class="o">(</span><span class="s">&#34;数学&#34;</span><span class="o">,</span> <span class="mf">99.0</span><span class="o">);</span>
</span></span><span class="line"><span class="cl">        <span class="n">scores</span><span class="o">.</span><span class="na">put</span><span class="o">(</span><span class="s">&#34;英语&#34;</span><span class="o">,</span> <span class="mf">99.99</span><span class="o">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">        <span class="n">Student</span> <span class="n">student1</span> <span class="o">=</span> <span class="k">new</span> <span class="n">Student</span><span class="o">(</span><span class="mi">1</span><span class="o">,</span> <span class="s">&#34;张三&#34;</span><span class="o">,</span> <span class="n">scores</span><span class="o">);</span>
</span></span><span class="line"><span class="cl">        <span class="n">Student</span> <span class="n">student2</span> <span class="o">=</span> <span class="n">student1</span><span class="o">.</span><span class="na">clone</span><span class="o">();</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">        <span class="n">student2</span><span class="o">.</span><span class="na">setId</span><span class="o">(</span><span class="mi">2</span><span class="o">);</span>
</span></span><span class="line"><span class="cl">        <span class="n">student2</span><span class="o">.</span><span class="na">setName</span><span class="o">(</span><span class="s">&#34;李四&#34;</span><span class="o">);</span>
</span></span><span class="line"><span class="cl">        <span class="n">student2</span><span class="o">.</span><span class="na">getScores</span><span class="o">().</span><span class="na">put</span><span class="o">(</span><span class="s">&#34;语文&#34;</span><span class="o">,</span> <span class="mf">100.0</span><span class="o">);</span>
</span></span><span class="line"><span class="cl">
</span></span><span class="line"><span class="cl">        <span class="n">System</span><span class="o">.</span><span class="na">out</span><span class="o">.</span><span class="na">println</span><span class="o">(</span><span class="n">student1</span><span class="o">);</span>
</span></span><span class="line"><span class="cl">        <span class="n">System</span><span class="o">.</span><span class="na">out</span><span class="o">.</span><span class="na">println</span><span class="o">(</span><span class="n">student2</span><span class="o">);</span>
</span></span><span class="line"><span class="cl">    <span class="o">}</span>
</span></span><span class="line"><span class="cl"><span class="o">}</span>
</span></span></code></pre></td></tr></table>
</div>
</div><p>输入：</p>
<div class="highlight"><div class="chroma">
<table class="lntable"><tr><td class="lntd">
<pre tabindex="0" class="chroma"><code><span class="lnt">1
</span><span class="lnt">2
</span></code></pre></td>
<td class="lntd">
<pre tabindex="0" class="chroma"><code class="language-fallback" data-lang="fallback"><span class="line"><span class="cl">Student{id=1, name=&#39;张三&#39;, scores={数学=99.0, 语文=100.0, 英语=99.99}}
</span></span><span class="line"><span class="cl">Student{id=2, name=&#39;李四&#39;, scores={数学=99.0, 语文=100.0, 英语=99.99}}
</span></span></code></pre></td></tr></table>
</div>
</div><p>what student2中修改的在student1中也起作用了。</p>
<p>这是因为使用Object中的clone()方法拷贝对象的时候，<span style="color: red">对于对象内部的数组、引用对象等都不拷贝，还是指向被拷贝对象中引用所在的地址，这种拷贝叫做浅拷贝</span>。</p>
<h3 id="深拷贝">深拷贝</h3>
<p>所谓的深拷贝就是对于那些只是拷贝引用而不拷贝对象的属性进行单独拷贝。比如Student类中的score属性是Map类型的，而Map类型是一个对象，在浅拷贝的时候只拷贝了应用，所以在这里应该白score也复制了，如下：</p>
<div class="highlight"><div class="chroma">
<table class="lntable"><tr><td class="lntd">
<pre tabindex="0" class="chroma"><code><span class="lnt"> 1
</span><span class="lnt"> 2
</span><span class="lnt"> 3
</span><span class="lnt"> 4
</span><span class="lnt"> 5
</span><span class="lnt"> 6
</span><span class="lnt"> 7
</span><span class="lnt"> 8
</span><span class="lnt"> 9
</span><span class="lnt">10
</span><span class="lnt">11
</span></code></pre></td>
<td class="lntd">
<pre tabindex="0" class="chroma"><code class="language-java" data-lang="java"><span class="line"><span class="cl"><span class="nd">@Override</span>
</span></span><span class="line"><span class="cl"><span class="kd">protected</span> <span class="n">Student</span> <span class="nf">clone</span><span class="o">()</span>  <span class="o">{</span>
</span></span><span class="line"><span class="cl">    <span class="n">Student</span> <span class="n">student</span> <span class="o">=</span> <span class="kc">null</span><span class="o">;</span>
</span></span><span class="line"><span class="cl">    <span class="k">try</span> <span class="o">{</span>
</span></span><span class="line"><span class="cl">        <span class="n">student</span> <span class="o">=</span> <span class="o">(</span><span class="n">Student</span><span class="o">)</span> <span class="kd">super</span><span class="o">.</span><span class="na">clone</span><span class="o">();</span>
</span></span><span class="line"><span class="cl">        <span class="n">student</span><span class="o">.</span><span class="na">scores</span> <span class="o">=</span> <span class="o">(</span><span class="n">Map</span><span class="o">&lt;</span><span class="n">String</span><span class="o">,</span> <span class="n">Double</span><span class="o">&gt;)</span> <span class="o">((</span><span class="n">HashMap</span><span class="o">)</span><span class="k">this</span><span class="o">.</span><span class="na">scores</span><span class="o">).</span><span class="na">clone</span><span class="o">();</span>
</span></span><span class="line"><span class="cl">    <span class="o">}</span> <span class="k">catch</span> <span class="o">(</span><span class="n">CloneNotSupportedException</span> <span class="n">e</span><span class="o">)</span> <span class="o">{</span>
</span></span><span class="line"><span class="cl">        <span class="n">e</span><span class="o">.</span><span class="na">printStackTrace</span><span class="o">();</span>
</span></span><span class="line"><span class="cl">    <span class="o">}</span>
</span></span><span class="line"><span class="cl">    <span class="k">return</span> <span class="n">student</span><span class="o">;</span>
</span></span><span class="line"><span class="cl"><span class="o">}</span>
</span></span></code></pre></td></tr></table>
</div>
</div><html>
<p style="color: red">这里值得注意的一点是被final修饰变量不能被克隆。</p>
</html>
<h2 id="参考">参考</h2>
<p>《设计模式之禅》</p>
</div><div class="post-footer" id="post-footer">
    <div class="post-info">
        <div class="post-info-line">
            <div class="post-info-mod">
                <span>更新于 2018-10-20</span>
            </div></div>
        <div class="post-info-line">
            <div class="post-info-md"><span>
                            <a class="link-to-markdown" href="/%E5%8E%9F%E5%9E%8B%E6%A8%A1%E5%BC%8F/index.md" target="_blank">阅读原始文档</a>
                        </span></div>
            <div class="post-info-share">
                <span><a href="javascript:void(0);" title="分享到 Twitter" data-sharer="twitter" data-url="http://example.org/%E5%8E%9F%E5%9E%8B%E6%A8%A1%E5%BC%8F/" data-title="设计模式之原型模式——浅拷贝和深拷贝" data-hashtags="设计模式"><i class="fab fa-twitter fa-fw" aria-hidden="true"></i></a><a href="javascript:void(0);" title="分享到 Facebook" data-sharer="facebook" data-url="http://example.org/%E5%8E%9F%E5%9E%8B%E6%A8%A1%E5%BC%8F/" data-hashtag="设计模式"><i class="fab fa-facebook-square fa-fw" aria-hidden="true"></i></a><a href="javascript:void(0);" title="分享到 Hacker News" data-sharer="hackernews" data-url="http://example.org/%E5%8E%9F%E5%9E%8B%E6%A8%A1%E5%BC%8F/" data-title="设计模式之原型模式——浅拷贝和深拷贝"><i class="fab fa-hacker-news fa-fw" aria-hidden="true"></i></a><a href="javascript:void(0);" title="分享到 Line" data-sharer="line" data-url="http://example.org/%E5%8E%9F%E5%9E%8B%E6%A8%A1%E5%BC%8F/" data-title="设计模式之原型模式——浅拷贝和深拷贝"><i data-svg-src="https://cdn.jsdelivr.net/npm/simple-icons@7.3.0/icons/line.svg" aria-hidden="true"></i></a><a href="javascript:void(0);" title="分享到 微博" data-sharer="weibo" data-url="http://example.org/%E5%8E%9F%E5%9E%8B%E6%A8%A1%E5%BC%8F/" data-title="设计模式之原型模式——浅拷贝和深拷贝" data-ralateuid="xxxx"><i class="fab fa-weibo fa-fw" aria-hidden="true"></i></a></span>
            </div>
        </div>
    </div>

    <div class="post-info-more">
        <section class="post-tags"><i class="fas fa-tags fa-fw" aria-hidden="true"></i>&nbsp;<a href="/tags/%E8%AE%BE%E8%AE%A1%E6%A8%A1%E5%BC%8F/">设计模式</a></section>
        <section>
            <span><a href="javascript:void(0);" onclick="window.history.back();">返回</a></span>&nbsp;|&nbsp;<span><a href="/">主页</a></span>
        </section>
    </div>

    <div class="post-nav"><a href="/%E4%BB%A3%E7%90%86%E6%A8%A1%E5%BC%8F/" class="prev" rel="prev" title="设计模式之代理模式和Java中的代理以及JDK动态代理的实现原理"><i class="fas fa-angle-left fa-fw" aria-hidden="true"></i>设计模式之代理模式和Java中的代理以及JDK动态代理的实现原理</a>
            <a href="/%E8%B4%A3%E4%BB%BB%E9%93%BE%E6%A8%A1%E5%BC%8F/" class="next" rel="next" title="设计模式之责任链模式">设计模式之责任链模式<i class="fas fa-angle-right fa-fw" aria-hidden="true"></i></a></div>
</div>
<div id="comments"><div id="valine" class="comment"></div><noscript>
                Please enable JavaScript to view the comments powered by <a href="https://valine.js.org/">Valine</a>.
            </noscript></div></article></div>
            </main><footer class="footer">
        <div class="footer-container"><div class="footer-line">由 <a href="https://gohugo.io/" target="_blank" rel="noopener noreffer" title="Hugo 0.109.0">Hugo</a> 强力驱动 | 主题 - <a href="https://github.com/dillonzq/LoveIt" target="_blank" rel="noopener noreffer" title="LoveIt 0.2.11"><i class="far fa-kiss-wink-heart fa-fw" aria-hidden="true"></i> LoveIt</a>
                </div><div class="footer-line" itemscope itemtype="http://schema.org/CreativeWork"><i class="far fa-copyright fa-fw" aria-hidden="true"></i><span itemprop="copyrightYear">2023</span><span class="author" itemprop="copyrightHolder">&nbsp;<a href="/" target="_blank">MC</a></span>&nbsp;|&nbsp;<span class="license"><a rel="license external nofollow noopener noreffer" href="https://creativecommons.org/licenses/by-nc/4.0/" target="_blank">CC BY-NC 4.0</a></span></div>
        </div>
    </footer></div>

        <div id="fixed-buttons"><a href="#" id="back-to-top" class="fixed-button" title="回到顶部">
                <i class="fas fa-arrow-up fa-fw" aria-hidden="true"></i>
            </a><a href="#" id="view-comments" class="fixed-button" title="查看评论">
                <i class="fas fa-comment fa-fw" aria-hidden="true"></i>
            </a>
        </div><link rel="stylesheet" href="/lib/valine/valine.min.css"><script type="text/javascript" src="https://cdn.jsdelivr.net/npm/valine@1.5.0/dist/Valine.min.js"></script><script type="text/javascript" src="https://cdn.jsdelivr.net/npm/autocomplete.js@0.38.1/dist/autocomplete.min.js"></script><script type="text/javascript" src="https://cdn.jsdelivr.net/npm/lunr@2.3.9/lunr.min.js"></script><script type="text/javascript" src="/lib/lunr/lunr.stemmer.support.min.js"></script><script type="text/javascript" src="/lib/lunr/lunr.zh.min.js"></script><script type="text/javascript" src="https://cdn.jsdelivr.net/npm/lazysizes@5.3.2/lazysizes.min.js"></script><script type="text/javascript" src="https://cdn.jsdelivr.net/npm/clipboard@2.0.11/dist/clipboard.min.js"></script><script type="text/javascript" src="https://cdn.jsdelivr.net/npm/sharer.js@0.5.1/sharer.min.js"></script><script type="text/javascript">window.config={"code":{"copyTitle":"复制到剪贴板","maxShownLines":50},"comment":{"valine":{"appId":"QGzwQXOqs5JOhN4RGPOkR2mR-MdYXbMMI","appKey":"WBmoGyJtbqUswvfLh6L8iEBr","avatar":"mp","el":"#valine","emojiCDN":"https://cdn.jsdelivr.net/npm/emoji-datasource-google@14.0.0/img/google/64/","emojiMaps":{"100":"1f4af.png","alien":"1f47d.png","anger":"1f4a2.png","angry":"1f620.png","anguished":"1f627.png","astonished":"1f632.png","black_heart":"1f5a4.png","blue_heart":"1f499.png","blush":"1f60a.png","bomb":"1f4a3.png","boom":"1f4a5.png","broken_heart":"1f494.png","brown_heart":"1f90e.png","clown_face":"1f921.png","cold_face":"1f976.png","cold_sweat":"1f630.png","confounded":"1f616.png","confused":"1f615.png","cry":"1f622.png","crying_cat_face":"1f63f.png","cupid":"1f498.png","dash":"1f4a8.png","disappointed":"1f61e.png","disappointed_relieved":"1f625.png","dizzy":"1f4ab.png","dizzy_face":"1f635.png","drooling_face":"1f924.png","exploding_head":"1f92f.png","expressionless":"1f611.png","face_vomiting":"1f92e.png","face_with_cowboy_hat":"1f920.png","face_with_hand_over_mouth":"1f92d.png","face_with_head_bandage":"1f915.png","face_with_monocle":"1f9d0.png","face_with_raised_eyebrow":"1f928.png","face_with_rolling_eyes":"1f644.png","face_with_symbols_on_mouth":"1f92c.png","face_with_thermometer":"1f912.png","fearful":"1f628.png","flushed":"1f633.png","frowning":"1f626.png","ghost":"1f47b.png","gift_heart":"1f49d.png","green_heart":"1f49a.png","grimacing":"1f62c.png","grin":"1f601.png","grinning":"1f600.png","hankey":"1f4a9.png","hear_no_evil":"1f649.png","heart":"2764-fe0f.png","heart_decoration":"1f49f.png","heart_eyes":"1f60d.png","heart_eyes_cat":"1f63b.png","heartbeat":"1f493.png","heartpulse":"1f497.png","heavy_heart_exclamation_mark_ornament":"2763-fe0f.png","hole":"1f573-fe0f.png","hot_face":"1f975.png","hugging_face":"1f917.png","hushed":"1f62f.png","imp":"1f47f.png","innocent":"1f607.png","japanese_goblin":"1f47a.png","japanese_ogre":"1f479.png","joy":"1f602.png","joy_cat":"1f639.png","kiss":"1f48b.png","kissing":"1f617.png","kissing_cat":"1f63d.png","kissing_closed_eyes":"1f61a.png","kissing_heart":"1f618.png","kissing_smiling_eyes":"1f619.png","laughing":"1f606.png","left_speech_bubble":"1f5e8-fe0f.png","love_letter":"1f48c.png","lying_face":"1f925.png","mask":"1f637.png","money_mouth_face":"1f911.png","nauseated_face":"1f922.png","nerd_face":"1f913.png","neutral_face":"1f610.png","no_mouth":"1f636.png","open_mouth":"1f62e.png","orange_heart":"1f9e1.png","partying_face":"1f973.png","pensive":"1f614.png","persevere":"1f623.png","pleading_face":"1f97a.png","pouting_cat":"1f63e.png","purple_heart":"1f49c.png","rage":"1f621.png","relaxed":"263a-fe0f.png","relieved":"1f60c.png","revolving_hearts":"1f49e.png","right_anger_bubble":"1f5ef-fe0f.png","robot_face":"1f916.png","rolling_on_the_floor_laughing":"1f923.png","scream":"1f631.png","scream_cat":"1f640.png","see_no_evil":"1f648.png","shushing_face":"1f92b.png","skull":"1f480.png","skull_and_crossbones":"2620-fe0f.png","sleeping":"1f634.png","sleepy":"1f62a.png","slightly_frowning_face":"1f641.png","slightly_smiling_face":"1f642.png","smile":"1f604.png","smile_cat":"1f638.png","smiley":"1f603.png","smiley_cat":"1f63a.png","smiling_face_with_3_hearts":"1f970.png","smiling_imp":"1f608.png","smirk":"1f60f.png","smirk_cat":"1f63c.png","sneezing_face":"1f927.png","sob":"1f62d.png","space_invader":"1f47e.png","sparkling_heart":"1f496.png","speak_no_evil":"1f64a.png","speech_balloon":"1f4ac.png","star-struck":"1f929.png","stuck_out_tongue":"1f61b.png","stuck_out_tongue_closed_eyes":"1f61d.png","stuck_out_tongue_winking_eye":"1f61c.png","sunglasses":"1f60e.png","sweat":"1f613.png","sweat_drops":"1f4a6.png","sweat_smile":"1f605.png","thinking_face":"1f914.png","thought_balloon":"1f4ad.png","tired_face":"1f62b.png","triumph":"1f624.png","two_hearts":"1f495.png","unamused":"1f612.png","upside_down_face":"1f643.png","weary":"1f629.png","white_frowning_face":"2639-fe0f.png","white_heart":"1f90d.png","wink":"1f609.png","woozy_face":"1f974.png","worried":"1f61f.png","yawning_face":"1f971.png","yellow_heart":"1f49b.png","yum":"1f60b.png","zany_face":"1f92a.png","zipper_mouth_face":"1f910.png","zzz":"1f4a4.png"},"enableQQ":false,"highlight":true,"lang":"zh-CN","pageSize":10,"placeholder":"你的评论 ...","recordIP":true,"serverURLs":"https://leancloud.hugoloveit.com","visitor":true}},"search":{"highlightTag":"em","lunrIndexURL":"/index.json","lunrLanguageCode":"zh","lunrSegmentitURL":"/lib/lunr/lunr.segmentit.js","maxResultLength":10,"noResultsFound":"没有找到结果","snippetLength":50,"type":"lunr"}};</script><script type="text/javascript" src="/js/theme.min.js"></script></body>
</html>
